Duisburg, Germany. As a manufacturer of products such as hot-dip galvanized sheet steel, thyssenkrupp Steel Europe AG is a key supplier to the automotive industry. A key element of its production is Hot Dip Galvanizing Plant 2 dating back to 1962, which operates uninterrupted 24/7 with the exception of regular maintenance shifts. Over its “life”, the plant has been repeatedly modernized. The most recent upgrade entailed optimization of the plant with the Simatic WinCC V7 Scada (Supervisory Control and Data Acquisition) system from Siemens to ensure maximum plant transparency. Improvements include animations affording operators a more intuitive grasp of processes. Use of the Webnavigator allows integration of WinCC into the local intranet, enabling the system to be accessed from anywhere in the company. With these additions, thyssenkrupp has made its production fit for the future. Hot Dip Galvanizing Plant 2 now benefits from greater efficiency and process reliability. Galvanized steel sheets play a key role in industrial manufacturing – first and foremost in the field of automotive engineering. To protect them from rust, the sheets need to be galvanized. thyssenkrupp Steel Europe is among the premier suppliers of this type of sheet steel. In its Hot Dip Galvanizing Plant 2, one of a total of eight plants of this type, the company produces around 440,000 tons of galvanized sheet steel every year. The process used entails steel strips welded together to form a continuous band being fed at a rate of around 120 meters a minute through the plant. After cleaning and recrystallization, the temperature of the steel is matched to the zinc bath to ensure an optimum bond of the zinc coating on the sheet. Following visual quality inspection by employees, the sheet is dried prior to customized packaging. Apart from regular maintenance shifts, the plant runs 24/7. Operating as what is called a bottleneck unit, unscheduled stoppages are particularly critical for the thyssenkrupp production plan, and ultimately also for customers relying on just-in-time deliveries, such as car manufacturers.

Continuous dutyTo ensure that the plant is available at all times, thyssenkrupp relies on the WinCC V7 Scada system as its control center. The most recent modernization of the plant, which has been operating since 1962, addressed a large number of different requirements: Virtualization to ensure independence from operating system cycles, creation of a redundant setup of the control system and access from more than 27 operator terminals, availability of production data and low training costs by basing the system on the familiar appearance of the existing system. During the project, which was fully planned, engineered and implemented within less than a year, thyssenkrupp worked together with Siemens Solutions Partner and WinCC Specialist focus Industrieautomation GmbH based in Merenberg. Switchover to the new system took place on schedule during one of the planned maintenance intervals in order to prevent an additional plant standstill.

The Simatic WinCC Scada System’s scalability and scope for future expansion were among the reasons why this system was chosen by focus. To ensure the system is failsafe, it runs on a redundant sever. The engineering station is a Simatic IPC547E industrial PC which permits adjustments to be made to the WinCC project independently of productive operation. To avoid overloading the WinCC server, the operator stations access an independent web server which allows the user-specific allocation of access rights with the option WebNavigator. For connection of the existing automation components over Profinet, focus opted for two additional Simatic IPC547E rack PCs. In the event of a power failure, an interruptible power supply ensures adequate power for a safe shutdown and to allow all relevant process values to be saved. Central long-term archiving of process data in the Simatic Process Historian data archive now ensures detailed long-term data evaluation. For support cases, focus can connect remotely to the plant over a secure VPN connection.

Fit for the futureThe modernization process has impacted on thyssenkrupp’s operations in a variety of ways. Operating screens have been made simpler and clearer, with animated sequences affording operators a more intuitive grasp of the process. Access rights enable control over who is afforded access to what and where. By means of serial coupling to the Enterprise Resource Planning System, plant data is now available across the company for long-term analysis.

Captions - all pictures Copyright thyssenkrupp Steel EuropeThe central control room is where all the threads of the hot dip galvanizing plant come together. Thanks to the clear layout, staff can keep an eye on all essential information at all times.The zinc coating is checked by an operator for any irregularities such as trapped air. At a strip speed of up to 120 m/s, this demands the highest levels of concentration.Numerous controllers, operator stations and virtual machines are integrated into the network of the hot dip galvanizing plant. Even the redundant Scada system itself and the archiving system run in virtual machines.With the central overview of the plant, all key stations can be assessed from the control room.